High-intensity discharge lamps are relatively compact and lightweight, yet they are capable of producing a significant amount of illumination. Furthermore, the bright white spectral profile of high-intensity discharge lamps, such as xenon arc lamps, closely resembles natural sunlight. Therefore, high-intensity discharge lamps are commonly used in solar simulators, such as for testing solar cells under carefully controlled laboratory conditions.
Continuous operation of high-intensity discharge lamps requires a significant amount of electrical energy and produces a significant amount of unwanted heat. Therefore, gas discharge flashlamps, such as xenon flashlamps, are often used, particularly when a large area (e.g., a large solar panel or solar array) is being illuminated. Gas discharge flashlamps produce a spectral profile that mimics solar illumination, but only for a brief moment (e.g., 1 or 2 milliseconds), thereby consuming significantly less energy and producing significantly less heat than continuously operated lamps.
Gas discharge flashlamps typically require a high-voltage trigger that creates initial gas ionization that, in turn, facilitates a high-current pulse through the flashlamp. The initial high-voltage trigger and subsequent high-current pulse form a high-pressure plasma within the flashlamp, which may degrade the flashlamp and, ultimately, may cause the flashlamp to fail (e.g., break).
Attempts have been made to avoid an in-service failure of a flashlamp. For example, a flashlamp can be visually inspected from time to time to determine whether the flashlamp has reached an end-of-lamp-life condition. However, such visual inspections tend to interfere with normal flashlamp operation. As another example, a flashlamp can be taken out of service after a predetermined number of pulses. However, doing so can be wasteful if the flashlamp still has a useful life.
Accordingly, those skilled in the art continue with research and development efforts in the field of flashlamps.